Green and Recyclable Medium for Asymmetric Hydrogenation of Benzalacetone Catalyzed by RuCl2(TPPTS)2-(S,S)-DPENDS

PEG400-H2O was a green and recyclable reaction medium for asymmetric hydrogenation of benzalacetone catalyzed by ruthenium achiral monophosphine complex, RuCl2(TPPTS)2 (TPPTS: P(m-C6H4SO3Na)3), which was modified by (S,S)-DPENDS (disodium salt of sulfonated (S,S)-1,2-diphenyl-1,2-ethylene-diamine). Under the optimized conditions, the chemoselectivity for 4-phenyl-3-buten-2-ol was 98.5% with a corresponding ee value of 74.3%. The resulting products could easily be separated from the catalyst by extraction with n-hexane. The catalyst immobilized on PEG400-H2O could be recycled and reused at least five times without significant loss of chemoselectivity and enantioselectivity.

摘要在聚乙二醇 400-水绿色可循环介质中, 以手性二胺 (S,S)-1,2-二苯基乙二胺二磺酸钠 ((S,S)-DPENDS) 与非手性钌膦络合物 ([RuCl2(TPPTS)2]2) 原位生成的水溶性钌膦二胺为催化剂, 考察了苄叉丙酮的选择性不对称加氢反应. 在优化的反应条件下, 羰基加氢产物 4-苯基-3-丁烯-2-醇的化学选择性和对映选择性分别为 98.5% 和 74.3%. 经正己烷萃取后, 催化剂即可从产物中分离出来. 循环使用 5 次后, 4-苯基-3-丁烯-2-醇化学选择性和对映选择性没有明显下降.

Graphical abstractPEG400/H2O was an efficient recyclable reaction medium for asymmetric hydrogenation of benzalacetone catalyzed by RuCl2(TPPTS)2-(S,S)-DPENDS. Utilizing this medium chemoselectivity for 4-phenyl-3-buten-2-ol was 98.5% and ee value of 74.3% was achieved. The catalyst immobilized on PEG400/H2O could be recycled and used repeatedly without significant loss of chemoselectivity and enantioselectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide